bind vg library with node.js nbind - how to set library and linking parameters in binding.gyp?

[subwaystation]

Hi vg team,

at the moment I am trying to build a JavaScript wrapper around your C++ library using https://github.com/charto/nbind.
However, I ran into some issues, see here https://github.com/charto/nbind/issues/35.

So at the moment I am stuck at the compilation step npm run -- node-gyp configure build. The problem is that the vg.hpp is not found:

  CXX(target) Release/obj.target/nbind/JS_VG.o
../JS_VG.cc:1:10: fatal error: 'vg.hpp' file not found
#include "vg.hpp"
         ^
1 error generated.

Here is my source file from which I want to invoke vg:

#include "vg.hpp"
#include "nbind/api.h"

namespace vg {
  // This inherits methods from VG for directly binding them when possible.
  class JS_VG : public VG {
    // Anything taking a callback will have to be wrapped!
    for_each_node(nbind::cbFunction lambda) { /* your code here */ }

    // Alternatively you can give your new implementation a new name.
    js_for_each_node(nbind::cbFunction lambda) { /* your code here */ }
  };
} // namespace

#include "nbind/nbind.h"

// You can rename your JS_VG reimplementation back to VG on the JavaScript side.
NBIND_CLASS(vg :: JS_VG, VG) {
  // You don't have to reimplement this, just tell nbind that it exists.
  method(normalize);

  // This C++ method is overloaded so we need to tell nbind which arguments it takes
  // (otherwise the C++ compiler cannot distinguish between overloads).
  multimethod(has_node, args(Node *));

  // If we want to bind several overloads, they need to be renamed uniquely
  // because nbind doesn't yet support overloading by type on the JavaScript side.
  multimethod(has_node, args(id_t), "has_node_id");

  // We've overloaded this with a new implementation.
  multimethod(for_each_node, args(nbind::cbFunction));

  // Alternatively if we renamed it uniquely, we can just rename it back here
  // and have nbind autodetect the arguments. Actually we can use camelCase
  // which is more common in JavaScript.
  method(js_for_each_node, "forEachNode");

  // Add an empty constructor
  construct<>();

  // Check if the graph is empty
  method(empty);

  // Generate has out of graph
  method(hash);
}

And here my binding.gyp file:

{
	"targets": [
		{
			"includes": [
				"auto.gypi"
			],
			"sources": [
				"JS_VG.cc"
			],
			"conditions": [
				["OS=='mac'", {
					"libraries": [
						"-lvg"
					]
				}],
			]
		}
	],
	"includes": [
		"auto-top.gypi"
	]
}

I tried putting libvg.a into the directory where I am building the stuff. Then I copied libvg.a into /usr/lib/libvg.a. All of this is not working. How do I have to set the compiler flags and the library stuff in order to compile it? Please help me out here.

For node-gyp see:
https://github.com/nodejs/node-gyp
https://gyp.gsrc.io/docs/InputFormatReference.md
https://gyp.gsrc.io/docs/UserDocumentation.md
https://github.com/nodejs/node-gyp/wiki/"binding.gyp"-files-out-in-the-wild

All the best.

[glennhickey]

You compiler's complaining it can't find vg.hpp. You can fix this with the
-I flag to tell it where to look. For a simple example of a C++ project
that links against vg, you can look at the Makefile here as a very basic
example

https://github.com/glennhickey/ultrabubble_eval

(which relies on the VGDIR variable hardcoded in the Makefile).

On Thu, Nov 10, 2016 at 11:05 AM, subwaystation notifications@github.com
wrote:

Hi vg team,

at the moment I am trying to build a JavaScript wrapper around your C++
library using https://github.com/charto/nbind http://url.
However, I ran into some issues, see here https://github.com/charto/
nbind/issues/35 http://url.

So at the moment I am stuck at the compilation step npm run -- node-gyp
configure build. The problem is that the vg.hpp is not found:

CXX(target) Release/obj.target/nbind/JS_VG.o
../JS_VG.cc:1:10: fatal error: 'vg.hpp' file not found
#include "vg.hpp"
^
1 error generated.

Here is my source file from which I want to invoke vg:

#include "vg.hpp"
#include "nbind/api.h"
namespace vg {
// This inherits methods from VG for directly binding them when possible.
class JS_VG : public VG {
// Anything taking a callback will have to be wrapped!
for_each_node(nbind::cbFunction lambda) { /* your code here */ }

// Alternatively you can give your new implementation a new name.
js_for_each_node(nbind::cbFunction lambda) { /* your code here */ }

};
} // namespace

#include "nbind/nbind.h"
// You can rename your JS_VG reimplementation back to VG on the JavaScript side.NBIND_CLASS(vg :: JS_VG, VG) {
// You don't have to reimplement this, just tell nbind that it exists.
method(normalize);

// This C++ method is overloaded so we need to tell nbind which arguments it takes
// (otherwise the C++ compiler cannot distinguish between overloads).
multimethod(has_node, args(Node *));

// If we want to bind several overloads, they need to be renamed uniquely
// because nbind doesn't yet support overloading by type on the JavaScript side.
multimethod(has_node, args(id_t), "has_node_id");

// We've overloaded this with a new implementation.
multimethod(for_each_node, args(nbind::cbFunction));

// Alternatively if we renamed it uniquely, we can just rename it back here
// and have nbind autodetect the arguments. Actually we can use camelCase
// which is more common in JavaScript.
method(js_for_each_node, "forEachNode");

// Add an empty constructor
construct<>();

// Check if the graph is empty
method(empty);

// Generate has out of graph
method(hash);
}

And here my binding.gyp file:

{
"targets": [
{
"includes": [
"auto.gypi"
],
"sources": [
"JS_VG.cc"
],
"conditions": [
["OS=='mac'", {
"libraries": [
"-lvg"
]
}],
]
}
],
"includes": [
"auto-top.gypi"
]
}

I tried putting libvg.a into the directory where I am building the stuff.
Then I copied libvg.a into /usr/lib/libvg.a. All of this is not working.
How do I have to set the compiler flags and the library stuff in order to
compile it? Please help me out here.

For node-gyp see:
https://github.com/nodejs/node-gyp http://url
https://gyp.gsrc.io/docs/InputFormatReference.md http://url
https://gyp.gsrc.io/docs/UserDocumentation.md
https://github.com/nodejs/node-gyp/wiki/"binding.gyp"-
files-out-in-the-wild http://url

All the best.

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[adamnovak]

In addition to copying libvg.a, a proper global install will need all the *.hpp files under vg/src and subfolders, and those under vg/include (after the build process populates it), to be somewhere in the global include directory (/usr/include, probably).

Unfortunately, in vg we have a bad habit of referring to our includes from dependencies without qualifying paths. So maybe you want to just dump them all into /usr/include/vg so they can find each other without gumming up the global include directory with things like "utils.h", and then pass a -I/usr/include/vg.

[subwaystation]

The issue has been solved, for a short tutorial see here: charto/nbind#35